Good morning kbod (at least for me its morning,lol)!
Let's start with the most important things and then work down:
(1)
First, the most important thing is your Fish-In Cycle (because that's what's keeping your fish alive!) You didn't report what the water change accomplished last night (probably because it was late and you didn't wait half hour for testing etc.)
So, again, you want to establish that you'll do tests at least morning and evening (at least until you get a feel for what to expect your water is doing.) If you find that one of the poisons has reached 0.25ppm or slightly above then its time for another 50% water change. If its 0.50ppm or higher, I'd say, that's more urgent and you'd need your water change soon and then probably another an hour later based on a test before the second change.
In your notebook or on paper, record the date, time, tank temp., ammonia, nitrite(NO2) and pH when you test. You can post it here too when asking questions or not, once you feel you understand it. pH is an easy test and if it stays pretty good then maybe you can slow down the number of times that's done after a while.
(2)
Getting "Mature Media" for your filter:
Yes, there are threads (I believe there's a pinned one at the top of "New to the Hobby") where you can post up your need for mature media. If you are very lucky, someone near Maplethorpe might see it and reply and you could set up a meeting. (Of couse, you could catch the next trans-Atlantic flight and drop in at my place and I'd give you some ceramic rings covered in bacteria...
) Anyway, don't worry too much about it, its rare to find someone to donate and your fish-in cycle will proceed without it, just more slowly, about a month we're talking.
(3)
Other chemicals you've got:
The "filter boost" is probably worthless (this is what they give customers instead of telling them it takes a month to prepare a filter, because otherwise they'd lose them as a customer and hobbyist usually!) but its also probably harmless, so you can keep putting it in if you want, can't hurt, we assume.
The stuff to treat "bad ammonia" I'd save and here's how I might use: Remember how if you see 0.50 or above of one of the poisons, ammonia or nitrite(NO2), your water change is more urgent, right? Well, if that happened but you had to go out and couldn't do the water change, then you could use some of this stuff. Its not as good as doing a water change, because it will mess up understanding your readings next time (ammonia will still look too high) but it might help in a pinch.
(4)
Odds and Ends:
When plant leaves get too brown to be saved, pinch just the leaf off at the crown (base of leaf stem) and you can keep hoping new leaves will sprout. The roots and crown can still hold future life sometimes even when all leaves are pinched off. But pruning is good because dead plant debris is also a cause of ammonia.
About the ammonia in your tap water: remember, its ppm (parts per -million-) so its a really, really tiny amount, so you can just think of it as giving your tea some "character!"
Because you have some ammonia in your tap water though, eventually, after you are cycled, we'll recommend maybe 25% water changes rather than 30% changed for your weekly gravel-clean-water-change maintenance, just a slightly smaller amount. Remember, this is *not* what you are worrying about now. For now just worry about your fish-in cycle as in number (1) up above.
About reading: Yes, reading here about the hobby is great. Look in the Beginners Resource Center and you can read quite a number of good articles. Also, many experienced members have great reading links in their "signature." I also think its great to read the threads of other beginners here and interact if you want, for some this helps them learn it better. Then there are other fascinating things in the other sections of the forum too! Its fun.
(5)
Hopefully TFF will help you have a better fish tank, Kaz and Kitty, and things will be looking up!
~~waterdrop~~